How did terricolous fungi originate in the Mediterranean region? A case study with a gypsicolous lichenized species

Abstract

Aim: The historical causes responsible for the wide distribution of terricolous, crustose lichenized fungi across the Mediterranean Basin and the Canary Islands have never been explored. Here, we used the terricolous, circum-Mediterranean/Macaronesian species Buellia zoharyi (Caliciaceae, Ascomycota) to infer the time frame, and the climatic, geological and ecological factors influencing the origin and current spatial distribution of this species. Location: Mediterranean Basin and Canary Islands. Methods: Data from two nuclear markers (nrITS and tef1) obtained from 226 specimens of 23 populations covering the entire distribution range of B. zoharyi were used to calculate genetic diversity indices and haplotype networks and to investigate population size changes and structure. Three secondary calibrations were used to estimate the timing of the divergence of B. zoharyi from its hypothesized sister species, B. elegans, and the diversification of B. zoharyi. Results: We found low nucleotide diversity and two geographically differentiated haplogroups, with a contact zone in the Iberian Peninsula. The three dating approaches established wide temporal windows for the divergence of B. zoharyi from B. elegans (Eocene-Pliocene) and its diversification (Miocene-Pleistocene). These intervals overlap with the origin and diversification ages found in other lichen-forming fungi and vascular plants inhabiting the Mediterranean region. Main conclusions: In the context of lichen biogeography, our results support ecological specialization as well as geological and climatic events as drivers of the evolutionary history of B. zoharyi in the Mediterranean. In particular, the combined effects of the Messinian salinity crisis and the subsequent Zanclean Flood on the availability of gypsum soils in the Mediterranean Basin, as well as the Quaternary climatic oscillations, seem to have collectively shaped the amount and distribution of B. zoharyi population genetic diversity. K E Y W O R D S biogeography, Buellia zoharyi, ecological speciation, gypsum soils, Messinian salinity crisis, Zanclean Flood

Multidisciplinary approach to describe Trebouxia diversity within lichenized fungi Buellia zoharyi from the Canary Islands

“…Specifically, this species predominantly grows on gypsum soils (Crespo and Barreno 1975;Barreno 1994;Trinkaus and Mayrhofer 2000), but occasionally some interesting populations of this species grow on basaltic lava flows in the Canary Islands (Etayo 2011; Giralt and Van den Boom 2011; Roux and Poumarat 2015). The presence of this lichen species in the Canary Islands was reported in Lanzarote (Trinkaus and Mayrhofer 2000), Fuerteventura (Van den Boom and Etayo 2006) and Tenerife (Chiva et al 2019), and populations in the other four Islands must be scarce or even non-existent. These three locations have similar ecological conditions e. g. the same high irradiance (5.5-5.7 KWh/m2) moreover, in the three locations B. zorayi grown forming biocrusts in areas with sparse vascular vegetation.…”

“…However, the WordlClim database reported different mean annual temperatures (MAT): 17°C in Fuerteventura and Lanzarote, and 20°C in Tenerife (https://www.worldclim.org; Hijmans et al 2005). Chiva et al (2019) analyzed mycobiont diversity in B. zoharyi in the Mediterranean region including those three Canary Island locations. They found low genetic diversity and two geographically differentiated haplogroups: one including populations from the Iberian Peninsula to Azerbaijan, and the other from the southern Iberian Peninsula, North Africa and the Canary Islands.…”

Species‐specific effects of biocrust‐forming lichens on soil properties under simulated climate change are driven by functional traits

“…S4). Buellia zoharyi is a widespread species in the Mediterranean and Macaronesian regions (Chiva et al ., 2019) and is particularly common in gypsum soils from central Spain (Concostrina‐Zubiri et al ., 2014; Ladrón de Guevara et al ., 2018).…”

Cladonia subturgida (Cladoniaceae, Lecanoromycetes), an overlooked, but common species in the Mediterranean region

“…In some studies about population genetics in the Mediterranean region, some patterns similar to those of Cladonia subturgida have been found, i.e. with scarce genetic variation and populations geographically little structured, for example in Buellia zoharyi (Chiva et al 2019) and Parmelina carporhizans (Alors et al 2017). The lack of geographical structure has been attributed to the high dispersal capacity of the species, to the absence of geographical barriers (Alors et al 2017) and to the fact that the habitats were not affected by glaciations.…”